A conventional sewing machine feed mechanism, as shown in FIG. 1, includes a feed belt 11 rotatably fitted on two spaced wheels 12a, 12b, a motor 13 connected to the feed belt 11 and driving the same to rotate, and a plurality of cylinders 14 connected to a pressure control system. When being driven by the motor 13 to rotate, the feed belt 11 brings fabrics placed between the feed belt 11 and a work table 10 to move horizontally into a stitch forming area of the sewing machine.
As can be more clearly seen in FIG. 2, the cylinders 14 respectively internally include a movable piston for actuating at least one pressing unit, and has a compressible fluid filled therein. The pressing unit includes rollers 15, pins 16, side brackets 17 and a pressing plate 18, and is in contact with an inner side of the feed belt 11. The pressure applied by the pressing unit against the transported fabrics can be adjusted via the compressible fluid in the cylinder 14 and the pressure control system.
The conventional sewing machine feed mechanism uses the cylinders 14 and the pressure control system connected thereto to adjust the pressure applied by the pressing units against the fabrics. Each of the cylinders 14 is communicably connected to an air-pressure tube and accordingly, involves relatively complicated mounting and dismounting procedures. Further, in the conventional sewing machine feed mechanism, every pressing unit requires one cylinder 14. Therefore, a large number of cylinders and air-pressure tubes are included in the feed mechanism to inevitably increase the manufacturing cost of the feed mechanism.
In view of the above disadvantages of the conventional sewing machine feed mechanism, it is desirable to develop an improved sewing machine feed mechanism that has simplified structure and reduced manufacturing cost, allows convenient mounting or dismounting thereof, and applies even pressure against the transported fabrics.